1. Field of the Invention
The present invention relates to a heat-resistant nickel-based alloy that can be used as a material for forming the stationary turbine vane of a gas turbine and other parts to be exposed to high temperatures.
2. Description of the Prior Art
Heat-resistant alloys used as materials for parts to be exposed to high temperatures, such as the stationary turbine vane of a gas turbine, include an Ni-based alloy which enjoys the effects of both strengthening through precipitation of an intermetallic compound Ni.sub.3 (Al,Ti), i.e., a .gamma.' phase, and strengthening through solid solution with Mo, W, etc., and a Co-based alloy strengthened through precipitation of a carbide.
In the Ni-based alloy, an increase in the amount of precipitation of the .gamma.' phase generally tends to lower the weldability of the alloy, though it improves the high-temperature strength of the alloy. For example, this is clear from the fact that an alloy increased in the amount of precipitation of the .gamma.' phase to improve the high-temperature strength thereof (Japanese Patent Publication No. 6,968/1979) is very poor in weldability, while an alloy decreased in the amount of precipitation of the .gamma.' phase to improve the weldability thereof (Japanese Patent Laid-Open No. 104,738/1989) is very low in high-temperature strength. On the other hand, the Co-based alloy, though generally good in weldability, is low in high-temperature strength and no remarkable improvement can be expected.
As is apparent from the foregoing, since the high-temperature strength of the Co-based alloy is limited, the Ni-based alloy must be improved in weldability without detriment to the high-temperature strength thereof.